Kenichi Tezuka

Bio: Kenichi Tezuka is an academic researcher from Tokyo Electric Power Company. The author has contributed to research in topics: Ultrasonic flow meter & Control valves. The author has an hindex of 10, co-authored 52 publications receiving 329 citations.

CFD Simulations and Experiments of Flow Fluctuations Around a Steam Control Valve

Abstract: Under certain opening conditions (partial opening) of a steam control valve, the piping system in a power plant occasionally experiences large vibrations. To understand the valve instability that is responsible for such vibrations, detailed experiments and CFD calculations were performed. As a result of these investigations, it was found that under the middle-opening (partial opening) condition, a complex three-dimensional (3D) flow structure (valve-attached flow) sets up in the valve region leading to a high pressure region on a part of the valve body. As this region rotates circumferentially, it causes a cyclic asymmetric side load on the valve body, which is considered to be the cause of the vibrations.

Assessment of Effects of Pipe Surface Roughness and Pipe Elbows on the Accuracy of Meter Factors Using the Ultrasonic Pulse Doppler Method

Abstract: The velocity profile of the flow in a pipe and its influence on the profile factor used with conventional flow meters were investigated with ultrasonic pulse Doppler measurements. From the measured velocity profiles, the influences of surface roughness and Reynolds number were characterized qualitatively and quantitatively. As pipe surface roughness changes during plant operation, the velocity profile changes, producing a change in the profile factor. Variation in the Reynolds number also influences the change in the profile factor. Experiments were conducted at high temperature and pressure to evaluate the ultrasonic pulse Doppler method for measuring the flow of nuclear plant cooling water. Helium gas bubbles provided sufficiently persistent ultrasonic reflectors when injected into high-pressure water, permitting the velocity profile of the flow to be obtained under high-temperature and high-pressure conditions using this method.

Ultrasonic flowmeter, wedge for ultrasonic flowmeter, method for setting ultrasonic transmitting/receiving unit, and ultrasonic transmitting/receiving unit

Abstract: [PROBLEMS] Using an ultrasonic flowmeter, a technique contributing to more accurate flowrate measurement by allowing transmission in both a wedge and a pipe wall and measuring flowrate more accurately is provided. [MEANS FOR SOLVING PROBLEMS] An ultrasonic transmitting/receiving unit comprises an ultrasonic transmitting means for emitting ultrasonic pulses at desired frequency along a measurement line from an ultrasonic transducer into a fluid to be measured in a fluid pipe, a flow-velocity distribution measuring means for receiving an ultrasonic echo (reflected wave A) reflected from the measurement region among the ultrasonic pulses emitted into the fluid and measuring the flow-velocity distribution of the fluid in the measurement region, a flowrate calculation means for calculating the flowrate of the fluid in the measurement region from the flow-velocity distribution of the fluid. The ultrasonic transmitting/receiving unit is of a clamp-on type. The distance from the ultrasonic transmitting means of a wedge to the outer wall of the fluid pipe and the fluid pipe thickness satisfy the condition that they are both integral multiples of λ/2 of the use frequency.

Three-phase flow measurement in the petroleum industry

Abstract: The problem of how to accurately measure the flowrate of oil–gas–water mixtures in a pipeline remains one of the key challenges in the petroleum industry. This paper discusses why three-phase flow measurement is still important and why it remains a difficult problem to solve. The measurement strategies and principal base technologies currently used by commercial manufacturers are described, and research developments that could influence future flowmeter design are considered. Finally, future issues, which will need to be addressed by manufacturers and users of three-phase flowmeters, are discussed.

Benefits and challenges of using smart meters for advancing residential water demand modeling and management

Abstract: Over the last two decades, water smart metering programs have been launched in a number of medium to large cities worldwide to nearly continuously monitor water consumption at the single household level. The availability of data at such very high spatial and temporal resolution advanced the ability in characterizing, modeling, and, ultimately, designing user-oriented residential water demand management strategies. Research to date has been focusing on one or more of these aspects but with limited integration between the specialized methodologies developed so far. This manuscript is the first comprehensive review of the literature in this quickly evolving water research domain. The paper contributes a general framework for the classification of residential water demand modeling studies, which allows revising consolidated approaches, describing emerging trends, and identifying potential future developments. In particular, the future challenges posed by growing population demands, constrained sources of water supply and climate change impacts are expected to require more and more integrated procedures for effectively supporting residential water demand modeling and management in several countries across the world. We review high resolution residential water demand modeling studies.We provide a classification of existing technologies and methodologies.We identify current trends, challenges and opportunities for future development.

NAWMS: nonintrusive autonomous water monitoring system

Abstract: Water is nature's most precious resource and growing demand is pushing fresh water supplies to the brink of non-renewability. New technological and social initiatives that enhance conservation and reduce waste are needed. Providing consumers with fine-grained real-time information has yielded benefits in conservation of power and gasoline. Extending this philosophy to water conservation, we introduce a novel water monitoring system, NAWMS, that similarly empowers users.The goal of our work is to furnish users with an easy-to-install self-calibrating system that provides information on when, where, and how much water they are using. The system uses wireless vibration sensors attached to pipes and, thus, neither plumbing nor special expertise is necessary for its installation. By implementing a non-intrusive, autonomous, and adaptive system using commodity hardware, we believe it is cost-effective and widely deployable.NAWMS makes use of the existing household water flow meter, which is considered accurate, but lacks spatial granularity, and adds vibration sensors on individual water pipes to estimate the water flow to each individual outlet. Compensating for manufacturing, installation, and material variabilities requires calibration of these low cost sensors to achieve a reasonable level of accuracy. We have devised an adaptive auto-calibration procedure, which attempts to solve a two phase linear programming and mixed linear geometric programming problem.We show through experiments on a three pipe testbed that such a system is indeed feasible and adapts well to minimize error in the water usage estimate. We report an accuracy, over likely domestic flow-rate scenarios, with long-term stability and a mean absolute error of 7%.

Industrial applications

Abstract: This first technical session is further developing the technological dimensions of technology transfer, with three illustrations of successful and representative industrial applications. It covers the cases of embedded autonomy in spacecraft applications, advanced avionics solutions for satellite communication and component hybridization for navigation.

Gas shut-off device

Abstract: An object of the present invention is to perform a suitable registration of a flow rate of appliances to promote the optimization of a usage time limitation function. In a gas shut-off device according to the invention, a flow rate detection unit measures a flow rate, a flow rate calculation unit calculates values of instant flow rates from a detection value, an average flow rate calculation unit obtains an average flow rate from the obtained instant flow rates, a flow rate change decision unit decides the presence or absence of a change in the flow rate based on the obtained average flow rate, a flow rate storage unit stores a value of the obtained average flow rate, an increase flow rate registration unit registers an amount of the flow rate change at the time of increase change decision by the flow rate change decision unit, a decrease flow rate re-registration unit reduces the registered flow rate near an amount of the flow rate change at the time of decrease change decision by the flow rate change decision unit, and re-registers and replaces it with a value of the average flow rate obtained by the average flow rate calculation unit after the reduction of the registered flow rate, and a shut-off unit shuts off the supply of gas when decided as an abnormality by an abnormality decision unit from the registered flow rate and a decision value.